Feed my sheep

"Feed my sheep" is a phrase I'm only too familiar with as a pastor's wife. It's what my husband is told he's supposed to do. It's also what Jesus told Peter to do, as well as "Feed my lambs".
Oddly enough, I'd never really though much about the difference. I think I assumed it was just for the sake of variety. But it's starting to take on a different significance...

I have no farming background, so my apologies if what follows is incorrect. But I know that sometimes lambs, especially new-born ones, have to be taken into the house, kept warm, and given milk via a bottle.
Contrast this with sheep. The job there is to take them to fields of new grass. The sheep can then get on and eat it. You don't have to pull up handfuls of the stuff and give it to them a mouthful at a time. You simply get them into the right environment, and let them do the rest.

Hand-feeding is obviously labour-intensive and time-consuming. But you assume that eventually it will no longer be needed. Then all you will need to do is lead the way to a field with good pasture and safe boundaries, and, for the most part, let the sheep get on with it. Obviously if there are particular dangers or if one is injured or struggling, then you have a responsibility to intervene. But otherwise, you should be able to leave the sheep there, and go back to making sure the lambs pull through.

So how come so many people who are supposedly mature in the faith still demand to be personally bottle-fed by the pastor and complain if they're not?
How difficult is it for a sheep to learn to eat grass???